With increasing development of science and technology, transfer platforms are widely applied to various fields. For example, a transfer platform is equipped with a linear motor to carry and transfer objects automatically. Moreover, the conventional transfer platform further comprises a ball screw. The cooperation of the ball screw and the motor is used for controlling the moved position of the transfer platform. Nowadays, the demands on the performance of the transfer platform are gradually increased. For example, the transfer platform needs to have many benefits such as high speed, low noise and high positioning precision. For achieving these benefits, a moving-magnet transfer platform was introduced into the market. Consequently, the mechanical transfer platform including the motor and the ball screw is replaced by the moving-magnet transfer platform.
Conventionally, the moving-magnet transfer platform comprises a mover part, a stator part and a driving part. The mover part is movable relative to the stator part. The mover part comprises a coil assembly with plural coils. The stator part is fixed and immobile. The stator part comprises a magnet assembly. The driving part issues a driving power. Moreover, the driving part controls the electric power to flow through the coils according to the relative positions between the coils and the magnet assembly. In response to the electric power, the coil generates a first magnetic field. The first magnetic field and a second magnetic field of the magnetic assembly interact with each other. Consequently, the mover part is correspondingly moved.
When the electric power flows through the coils of the coil assembly, a great amount of heat is generated. Consequently, during the operation of the conventional moving-magnet transfer platform, the operating temperature is increased. For reducing the operating temperature and protecting the moving-magnet transfer platform, an additional heat dissipating mechanism is necessary. Since the coil assembly is the main component of the mover part and the mover part is continuously moved during the operation of the moving-magnet transfer platform, the positions of the plural coils are continuously changed. Under this circumstance, the moving-magnet transfer platform is complicated and the heat dissipating efficacy is impaired.
Since the coil assembly is the main component of the mover part, the coils of the coil assembly receives electric power through a power cable. Moreover, since the mover part is continuously moved during the operation of the moving-magnet transfer platform, a drag chain is used to tow and protect the power cable. The use of the drag chain increases the fabricating cost of the moving-magnet transfer platform. Moreover, due to the drag chain, the available inner space of the moving-magnet transfer platform is reduced. Since the mover part is continuously moved, the power cable connected with the plural coils is readily abraded.
As mentioned above, the magnet assembly is the main component of the stator part, and the coil assembly is the main component of the mover part. For allowing the mover part to be moved relative to the stator part in a specified range, the area of the magnet assembly must be as large as possible. Under this circumstance, the stator part needs a large number of permanent magnets to form the magnet assembly. Since the material cost of the permanent magnets is high, the fabricating cost of the conventional moving-magnet transfer platform is increased.
As mentioned above, the driving part of the conventional moving-magnet transfer platform issues the driving power. Moreover, the driving part needs to control the electric power to flow through the coils. Consequently, the circuitry of the driving part is more complicated. During the process of switching the electric power to the coils, current fluctuation possibly occurs. Due to the current fluctuation, the working status of the driving part is unstable.
Therefore, there is a need of providing an improved moving-magnet transfer platform in order to overcome the above drawbacks.